Automobiles involved in crashes frequently catch fire and trap and burn the occupants. This is usually caused by the release of gasoline in the vicinity of a sparking wire resulting from a rupture of some part of the car's electrical system and from the fact that the ruptured electrical system is still connected to the battery.
For example, a rear-end collision which tears loose and ruptures the car's gas tank typically ruptures the electrical line which is connected to the gas level gauge. This broken line sparks as long as it remains connected to the car battery.
There is a popular belief that a gasoline fire may arise when raw gasoline pours onto a heated engine block. This, however, is a false belief as the flash point of gasoline is considerably higher than the temperature at its hottest of an engine block.
The vast majority of fires in crashed automobiles results from the exposure of a "hot" wire and from the fact that the exposed wire remains electrically connected to the car battery.